Wired for Monogamy

Bryce J. Christensen and Robert W. Patterson

New Research has highlighted numerous studies that link monogamy, or the discipline of confining sexual relations throughout life to one exclusive lover—to one’s husband or wife—to physical and emotional health. Now comes a study by researchers at the Universities of Michigan and Wisconsin that finds higher levels of depression among parents who bear children through more than just one opposite-sex partner, a behavior that could be called promiscuous fertility but which the experts euphemistically term “multipartnered fertility,” or MPF for short.

Kristin Turney and Marcia J. Carlson based their study on three waves of data from Fragile Families and Child Wellbeing Study, a longitudinal study of a cohort of American parents, disproportionately unmarried at the baseline, over a five-year period beginning at the birth of their child. Among the nearly 6,600 mothers and fathers in the researchers’ sample, 26 percent of mothers and 25 percent of fathers had reported MPF in the first year of the survey. Moreover, 18 percent of mothers and 15 percent of fathers reported, at mid-point, having had a major depressive order in the previous twelve months.

To explore the association between these two variables, the researchers used three types of bivariate and multivariate tests: a random-effects model, which captures both prior and subsequent MPF; a fixed-effects model capturing only MPF among the relatively small numbers of mothers and father that reported such behavior after the first wave; and a logistic regression to examine depression that occurs before MPF.

The random-effects model demonstrated a robust correlation between MPF and depression. Mothers reporting MPF, relative to their peers with children with only one father, were 1.66 times more likely to report depression (p<0.001). The results for fathers were almost identical (Odds Ratio, 1.76; p<.0.001). Moreover, MPF remained a significant predictor of depression even in multivariate models, one that controlled for a variety of background characteristics at baseline, and a second model that controlled for marital status.

The fixed-effects model, however, yielded no statistically significant effects between depression and mothers’ or fathers’ reporting having had a child by another partner in between the survey waves. The researchers believe these findings are due to the small number of parents reporting new MPF between the waves of the survey, as well as the small number of parents reporting changes in depression. As they state: “There is simply not enough change in independent and dependent variables to identify an effect.”

The differences between the random- and fix-effects models might suggest that depression is a cause, not a consequence, of MPF. However, in the study’s third set of tests, depression reported in the first wave predicted subsequent MPF only in bivariate analysis, not the multivariate model that controlled for baseline characteristics and marital status. The full model’s results indicate that the “mental health of either parent may be a factor in their breaking up and, thus, a risk factor for each parent being at risk of a new MPF.”

Even though the relationship between depression and MPF may work both ways, Turney and Carlson’s study raises concerns about the childbearing patterns of many Americans. Keep in mind that it is highly unlikely that their sample includes the extremely rare but legitimate case of a young widow having another child through remarriage to a widower. No, in all these cases under review, MPF occurs either outside the marital bond or within a second intimate union. Turney and Carlson should therefore not be surprised that their findings document another side-effect of the loss of monogamy and marriage as social ideals.